Sanjo refers to the playing of an instrument solo to the accompaniment of janggo (hourglass-shaped drum), moving from slow to fast rhythm in four to six movements. Geomungo Sanjo is Korean instrumental folk music played solo with geomungo (six-stringed zither). Geomungo, which is also called hyeongeum (literally “black zither”), is said to have been made by Wang San-ak during the Goguryeo Period (circa 37 BC - 668 AD). It has six silk strings made of twisted silk thread tied to a wooden body 1.5m long and 25cm wide. A player sitting on the floor plays it while it is placed on his/her lap the way one plays a guitar, with the left hand tuning melody with string support called “gwae” and the right hand striking strings with thin bamboo (“suldae”). Geomungo Sanjo was first played by Baek Nak-jun in 1896 (33rd year of Emperor Gojong’s reign), but some people said that it was music that degraded the gracefulness of geomungo. Thus, it was only years later that a particular type of geomungo playing was accepted by majority of the people. At first, it was composed of monotonous melodies or rhythms; gradually, however, exquisite and complicated rhythms were added. Geomungo Sanjo has five rhythms: jinyangjo (slow), jungmori (moderate), jungjungmori (moderately fast), eonmori (irregular), and jajinmori (fast). Overall, its melodies are made up of ujo (calm and steadfast feeling), which appears in the first and middle parts of each movement, and gyemyeonjo (sad, soft, and plaintive feeling), which appears mostly at the end of each movement. Geomungo Sanjo is a piece of music containing a sense of subdued masculinity, featuring moderate yet grand and unrestricted feeling; its rhythms, slow and fast, express the sense of delight, anger, sorrow, and joy well.